1. Field of the Invention
The present invention relates to a step-and-repeat pattern transfer device and method for preparing masks or drawing a pattern directly over the surface of a semiconductor wafer.
2. Technical Background of the Invention
According to a step-and-repeat pattern transfer method, an original image is focused over an object through a high resolving power lens so as to prepare photomasks or draw patterns over the surfaces of semiconductor wafers.
In this case, due to the thermal treatment or the like, the sizes of a semiconductor wafer vary, but the reduction of a high resolving power lens cannot be varied.
Therefore, there has been employed a method for varying the distance over which is stepped a focused image or cooling an object so as to reduce its size. In view of a time factor, the former is more practical, but accurate corrections cannot be made.